The present invention relates to a conductive ball transferring apparatus and method for attaching conductive balls and transferring them onto predetermined positions, and relates to a conductive ball supplying apparatus and method for supplying the conductive balls in an arrangement pattern to the transferring head of this transferring apparatus.
As methods of forming metal bumps for electrodes on a substrate or electronic components, known are those of placing conductive balls, such as solder balls, onto the electrodes to form solder joints. For the placement of conductive balls, a method of vacuum-suck and transferring conductive balls with a transferring head is widely used. This method allows the placement of the conductive balls onto predetermined positions by the steps of moving a suction tool of the transferring head with the conductive balls vacuum-sucked into suction holes provided in the bottom face of the suction tool and thereafter stopping the vacuum suction. In order to attach the conductive balls onto the bottom face of the suction tool, conventional methods include the steps of lowering the suction tool toward a ball vessel that pools a large number of conductive balls therein, and vacuum-suck the balls from suction holes with the bottom face of the suction tool sunk in a layer of conductive balls.
However, the above method of sucking up the conductive balls from the ball vessel directly onto the suction tool has had the following problem. Since the conductive balls in the ball vessel have been thrown in a random fashion and are not arranged, it is difficult to suck up the conductive balls into all the respective suction holes in the bottom face of the suction tool quickly without fail. To address this problem, means for promoting the suction of the conductive balls, e.g. blowing gas into a layer of conductive balls to move them, and vibrating the suction tool in relation to the layer of conductive balls, have been needed. It has taken a considerable time to suck the conductive balls into all the respective suction holes without fail. Thus, conventional apparatuses of transferring conductive balls had problems in quickly sucking up the conductive balls onto the transferring head.
The present invention addresses the problem discussed above. It is, therefore, an object of the present invention to provide a conductive ball transferring apparatus that allows quick suction of the conductive balls onto a transferring head and to provide a conductive ball supplying apparatus suitable for the transferring apparatus.
The conductive ball transferring apparatus of the present invention is comprised of:
(a) an arranging member having in its top face a plurality of recesses in a predetermined arrangement pattern, each capable of receiving one conductive ball therein;
(b) a tilting mechanism for tilting the arranging member with respect to a horizontal plane;
(c) a speed controller for controlling moving speeds of the conductive balls that move along the top face of the tilted arranging member in a direction the arranging member has been tilted; and
(d) a transferring head for picking up the conductive balls arranged on the arranging member and transferring them onto predetermined positions.
The conductive ball transferring method of the present invention includes the steps of:
(a) tilting with respect to a horizontal plane an arranging member having in its top face a plurality of recesses in a predetermined arrangement pattern, each capable of receiving one conductive ball therein;
(b) arranging the conductive balls into the recesses by moving the balls along the top face of the tilted arranging member at a predetermined speed in a direction the arranging member has been tilted; and
(c) picking up the arranged conductive balls and transferring them onto predetermined positions.
The above transferring apparatus and method can stabilize the moving speeds of conductive balls, and allow the conductive balls to be quickly arranged into the recesses without fail and promptly picked up by the transferring head onto predetermined positions.
The conductive ball supplying apparatus of the present invention is comprised of, for example, the above components (a), (b), and (c) of the conductive ball transferring apparatus of the present invention, and is an apparatus for supplying the conductive balls in an arrangement pattern to the above transferring head.
The conductive ball supplying method of the present invention is comprised of, for example, the above steps (a) and (b) of the conductive ball transferring method of the present invention, and is a method for supplying the conductive balls in an arrangement pattern to the above transferring head.
The above supplying apparatus and method can stabilize the moving speeds of conductive balls, and allow the conductive balls to be arranged into the recesses of the arranging member quickly without fail.